Bioconjugated systems

It is also interesting that rod assemblies can be apphcable to biomimetic or bioconjugate systems, hi Sect. 2.7, artificial nucleic acid complexes consisting of amphiphihc rods and linear nucleic acid polymers showed single twisted right-handed hehcal fibers. In addition, carbohydrate-coated supramolecular objects self-assembled by rod-coils or wedge-coils revealed outstanding fig-... 

Several dendrimeric borane and carborane systems have been developed for use as boron-delivery agents.147 In vitro tests with a boronated dendrimer-epidermal growth factor bioconjugates indicated that they are endocytosed, resulting in the accumulation of boron in lysosomes. 

Brus C, Petersen H, Aigner A, Czubayko F, Kissel T (2004) Physicochemical and biological characterization of polyethylenimine-graft-poly(ethylene glycol) block copolymers as a delivery system for oligonucleotides and ribozymes. Bioconjug Chem 15 677-684... 

The advantage of the click reaction for bioconjugation is that the reactant pair is not reactive with any other functional group encountered in biological systems. This property of... 

The technology of bioconjugation has affected every conceivable discipline in the life sciences. The application of a myriad of available chemical reactions and reagent systems for creating novel complexes with unique activities has made possible the assay of minute quantities of substances, the in vivo targeting of molecules, and the modulation of specific biological processes. Modified or conjugated molecules also have been used for purification, detection, or location of specific substances, and in the treatment of disease. 

The rapid turnover rate of some enzymes allows ELISAs to be designed that surpass the sensitivity of radiolabeling techniques. In addition, substrates can be chosen to produce soluble products that can be accurately quantified by their absorbance or fluorescence. Alternatively, substrates are available which form insoluble, highly colored precipitates, excellent for localizing antigens in blots, cells, or tissue sections. The flexibility of enzyme-based assay systems makes the chemistry of enzyme conjugation one of the most important application areas in bioconjugate techniques. 

Barth, R.F., Adams, D.M., Soloway, A.H., Alam, F., and Darby, M.V. (1994) Boronated starburst den-drimer-monoclonal antibody immunoconjugates Evaluation as a potential delivery system for neutron capture therapy. Bioconjugate Chem. 5, 58-66. 

Tadayoni, B.M., Friden, P.M., Walus, L.R., and Musso, G.F. (1993) Synthesis in vitro kinetics, and in vivo studies on protein conjugates of AZT Evaluation as a transport system to increase brain delivery. Bioconjugate Chem. 4, 139-145. 

Scheme 4. Preparation of bioconjugates using an N2S4 ligand system.

Despite the promising possibilities offered by the different types of nanoparticles, their routine use is still strongly limited by the very small number of commercially available systems and the limited amount of data on their reproducibility (in preparation, spectroscopic properties, and apphcation) and comparability (e.g., fluorescence quantum yields, stability) as well as on their potential for quantification. To date, no attempt has yet been published comparing differently functionalized nanoparticles from various sources (industrial and academic) in a Round Robin test, to evaluate achievable fluorescence quantum yields, and batch-to-batch variations for different materials and surface chemistries (including typical ligands and bioconjugates). Such data would be very helpful for practitioners and would present the first step to derive and establish quality criteria for these materials. 

A typical clearance profile and curve-fitting of these bioconjugates in a rat with normal renal function is shown in Fig. 16. The time constant is the relevant quantifiable measure for how fast the agent clears from the vascular system. Figs. 17 and 18 compare the plasma clearance profile of different fluorescein conjugates in normal and ligated rat kidneys. The clearance profile followed the... 

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